Variable speed power transmission



Dec. 21, 1931 A. LYSHOLM ET AL 2,102,634

VARIABLE SPEED POWER TRANSMISSION Original Fil'ed March 3, 1933 5 Sheets-Sheet l /J A oRNEY Das. 2.1, 19371.

A. LYsHoLM Er AL VARIABLE SPEED PowEE 'rRANsMIssIoEv original Filed March 3, 1933 ssheets-sheet 2 Dec.,21, 1937i( A. LYsHoLM ET AL VARIABLE SPEED POWER y'TRANSMISSION 5 Sheets-Sheet 3 Original Filed March 3, 1933 lull W17@ @ATTORN Y Dec. A21, 1937. A. I YsHoLM ET A1.

I VARIABLE SPEED POWER TRNSMISSION original Filed March s, 19:53

5 Sheets-Sheet 4 A. LYSHOLM ET AL I VARIABLE SPEED POWER TRANSMISSION Original Filed March 3 1933 5 Sheets-Sheet 5 y from any of the several conditions of drive to4 Patented Dec. 21, 19/37 y 'i UNITED -STATES VARIABLE srEED POWER mANsMrssrN Ali. Lysholm, Fred Harney, and Gsta Wahlsten, Stockholm, Sweden, assignors to Aktiebolaget Ljungstroms ngturbin, Stockholm, Sweden, a corporation o! Sweden l A Application March 3, k1933, Serial. No. l659,5ii0.

Renewed July 30, 1938. In Germany January 12 Claims.

This application is a continuation in part with respect to our copending application Serial No. 585,440 iiled January 8, 1932 (Pat. No. 1,900,119. fgranted March 7, 1933) and relates back, so far as herein continued, for all dates and rights incident to the iling of said lapplication Serial No. 585,440 and foreign applications corresponding thereto. i

f 'The present invention relatesto variable-speed power transmissions and has particular reference to variable-speed power transmissions of the type in which hydraulic variable speed mechanism is combinedwith mechanical power transmitting mechanism to provide for automatic'variablespeed ratios and positive direct drive in forward speeds and a variablespeed reverse.

In its several -phases the invention aims to improve -upontransmissions of the above stated Y character, particularly with respect .to the following features. In the transmission ,as a whole it is a principal object oi? the invention to provide a transmission of maximum compactnessboth 'as to axial and transverse dimensions. A further object is to provide in the transmission as a whole an improved arrangement whereby it `is possible to obtain a very powerful braking effect from the enginefvdue to the characteristics of the hydraulic part of the mechanismand to make this braking effect available at all times. In the control mechanism. a principal object of the invention is to provide for improved control whereby drive through the transmission may be altered any other, such, for exaxnpiaas from forward to reverse and vice versa. with the minimum of `shock and maximum 4facility, regardless of the y.

speed of operationy of the transmission. i All of the above principal objects and the fur-A ther and more detailed objects "of the invention will more fully. appear in the ensuing; description oi suitable forms of apparatus for carrying the -inventioninto effect.

' In the accompanying drawings forming of this specification:

Fig.. 1 is a central longitudinal section of a transmission embodying the invention;

Fig. 2 is a section taken on the line 27-2 ,oi' Fig. 1; Fig. 3 is a section taken on the line 3-3`of Fig.

,1 and showing control mechanismbmitted from Fig. 1;v

Fig. 4 is aside elevation of part oi Fig. 3;

. Fig. 5 is 'a section taken on the line B-B of E Fig. 3 showing-a detail of control parts illustrated in Figs. 3 andj4; "f

a part' Fig. 6 is a side elevation oi' part of the transmission shown in Fig. 1 and including certain control parts Fig. '7 is a view similar to Fig. 1 showing part of another form oi transmission;

',Fig. 8 is a section takencnI the lines 3--8 in Figs. 'I and 10;- .Fig. 9 is a section Figs. 7 and 1li: Fig.'10 is a section of Fig. 8;

Fig. 11 is a fragmentary of apart of Fig. 7;

- Fig. 12 is a section on showing part of the control mechanism; and

Fig. 13 is a section similar to Fig. 1, of a part of another form oi transmission.

taken on the lines 31-9 in taken on the trie in ln view on enlarged scale the line i2-I2 of Fig.` 8,

6 the form oi' transmission lillustrated therein comprises a casing i3 adapted to be non-rotatably mounted in the frame of a vehicle or the like and providing a main annular chamber il for circulation oi operating fluid.

nalled in the bearings, and a disc-like impellery Referring now more particularly to Figs. 1 to aotatably mounted within casing m and man i part It locatedwithin chamber li and carrying a ring oi impeller or pump bladesy Il, the axially inner ends oi which are joined by an annular ting la. Amts forward end the shaft part is of the primary member has splined thereto a clutch plate I9. i v

The secondary or driven member 2li of the' hydraulic power transmitting mechanism comprises a hollow shaft part 2i rotatably mounted in co'- axial alignment with the shaft part it and supported inI housing i0 by bali bearing 22. Member 20 also comprises an impelled or turbine Apart 23 situated in chamber i I and comprising a disclike portion carrying a ringof turbine blades 24 which atl their inner ends are joined by and support an annular ring 2l. Ring 25 extends radially outwardly from the portion attached to blades 24 and at its outer part has an 'usually extendingA circular flange 26 which supports a ring of radially extendln'g'turbine blades, the outer ends or which extend to within a short distance of the casing I0. Between the rings otturbine blades 21 and 24, there is situated a 'ring of stationary de blades 28 secured at one end't'o ring- 29 part and part 32 and the space between pacldng ends to anannular ring 36 situated in a recess 'inpart25.

'Ihe axially inner end of the hollow shaft part I5 of the driving member is enlarged to provide an internal pilot bearing 3| for the journal provided by an axially extending bearing part 32 fixed to the inner end of the shaft 'part 2 I. Preferably, the impeller part 23 is keyed to the shaft part I2| and the bearing part 32 is screwed on the end of shaft part 2| as a locking member, suitable packing being provided between parts 2| and 32 to prevent leakage of operating fluid therebetween from the chamber Il.

Between the part 32 and the hollow shaft part I5, packing is provided to prevent ow of 'fluid which may pass bearing 3| to the space within the hollow shaft parts. This packing means comprises, in the present embodiment, a packing ring 33 xed to the shaft part I5 and having a radially extending face against which face packing ring 34 abuts. Ring 34 is pressed against ring 33 by means of a coil spring 35 located between this ring 34 and part 32 is sealed by means of an expansible bellows member 36'attached to parts 32 and 34.

Similar packing means is provided between the Journal bearing i3 and bearing |2. This packing means comprises a bearing ring 31 fixed Vto the shaft part I5 and having a radially extending bearing surface against whichthe stationary packing ring 36 is pressed by means of spring 36.

Spring 36 abuts against a part attached to the stationary casing structure and ring 3 6 is connected to thisfstationary part by means of expansible bellows member 46.

Similar packing means is provided between the driven member and the bearing 22 supporting the shaft part 2|. This packing means comprises a packing ring 4| fixed to shaft 2| and a cooperating packing ring 42 pressed against ring 4| by means of spring 43 located between ring 42 and a stationary part 44 attached to the casing. The space between Vring 42 and part 44 is closed by means of the expansible bellows 45 attached at its ends to these two parts.

Extending through the bore provided by the hollow shaft parts i6 and 2| is shaft 46, supported at its forward end in ball bearing 41 and at its rearward end in bearing 46. Adjacent to its forward end shaft 46 has splined thereto the clutch plate 4S.

Shaft 66, which may be any suitable power shaft 4 and which in the present instance is indicated as the crank shaft of an engine or the like, has

secured thereto the fiywheel 6| which provides a housing for mounting bearing 41 and also proring 52 which is axially shiftable with respect to the ily-wheel but not rotatable with respect thereto. An annular cover plate 53 suitably bolted to the fly-wheel provides a' clutch surface 54 on its inner face and the ily-wheel provides'lv clutch surface 55 opposite the surface 54. `Ringl 52 is shifted axially by means 'of a series of p eripherally spaced axially extending -pins'56 which project through the cover plate 53 and at their outer ends are pivoted to levers51. Levers 51 are in turn pivoted intermediate their ends to supports 56 secured to the cover plate 53. At their radially innerends 1evers451 engage suitable rel teeth 66 projecting .part 66.

63. The inner race of bearing 62 isilxed to onel end of a sleeve member 64. which at its other end is guided on a journal on the stationary part 65 bolted. to a part in ,the main casing. Sleeve member 64 is provided with an external annular groove 66. Parts 6| and 64 are axially slidable with 'respect to parts 63 and 65 and part 6| is rotationally movable with respect to part 64 due to the interposition of bearing 62.

Casing I6 is provided with apair of aligned transversely extending lbearings 61 and 66 (see Fig. 2) in which are removably xed pins 66 and 16. The inner ends of these pins provide bearings for a yoke 1| having arms 12 and 13 which carry on suitable pins the blocks 14 and 15 engaging the groove 66. Yoke 1|v also has an arm 16 extending outwardly through a suitable opening in the housing and adapted to be connected to operating mechanism to be described.

We will now describe the means for transmittingpower from the shaft part 2| or the shaft 46 to the driven shaft 11 and for eecting reversal of direction of the driven shaft 11. Shaft part 2`| has fixed to its rearward end, axially outside of bearing 22, a ring part 16 having a plurality of faces thereon and forming the inner ring of an overrunning clutch indicated generally at 16.-

Shaft 46 at its rearward end has 'fixed thereto a cup-shaped part 66, the outer rim of which provides a ring 6| radially outsideof ring 16 and forming the outer ring of the overrunning clutch 16. Between rings 16 and 6| are located a pluralityof rollers 62 adapted to grip in thewedge. shaped spaces provided between the two rings and urged against the confronting faces of the rings by means of springs 63 carriedv on suitable pins 64 projecting axially from a radially extending Hange adjacent to the inner clutch ring'16 and fixed with respect thereto. f

Journalled on the outer face of ring 6|, as by v of the ange 96 provides a seat for the outer race of bearing is supporting the, rearward end of shaft 46.

Driven shaft l1 has a radially extending fiange 9| at its forward end and to this is secured the cup-shaped member 62 having at its forward end a series of axially extending clutch teeth 33 and a series of radially inwardly projecting teeth 54` 'providing 'an internal gear. Journalled on each of the pins 61 is a pinion gear 65, the teeth of which mesh with teeth 64 andalso with gear from the hub portion of the Axially slidable on a plurality of t th or splines on the outer circumference of part 6is the annular ring 96 having a set of axially projecting teeth 66 and at one side adapted to engage teeth V63 on part 62 and a setof teeth |66 adapted to engage' a set of fixed axially 'extending teeth |6| formed on the smtionary casing part |62. Ring 66 has an externalfgroove |63.

The casing part |64 bolted to the main casing part |6 supports two axially aligned pins |66 and |66 the inner ends of which provide pivots'for ,the yoke |67. Yoke -Il'l has arms |66 and l y 2,102,634 carrying blocks II0 and III situated in the fixed thereto lever III which at its end is conabove assumed sidewise movement of the control nected by means of a suitable ball and socket` connection (see Fig. 6) to link |I8, which at its other end by means of a second ball and socket connection is connected to the end of arm I6 on yoke II which projects through the casing.

Thelower end of lever ||5 is flattened as at II9 and extends into a slot |20 in a block |2I pivoted at the end of alever |22 which is pivoted to the upwardly projecting end |23 of the pin |06. Pin |06 is keyed to yoke |01l so as to turn the yoke when this pin is turned in its bearing. The

. lower flattened end I I9 of lever I I5 is notched at |24 to receive the projection at the center of the slot in block |2I. Lever |22 is pressed upwardly by'means of a leaf spring |25.

vThe operation ofthe apparatus in its different positions of control is as follows. It is assumed that the chamber II of the hydraulic mechanism is filled with operating fluid.` In Figs. 4 to 6 the control lever is shown in its neutral or upright position and it will be evident that the mounting of the leverA permits it to be moved both forward and backward with respect to the transmission and sidewise as well.N In Fig. 1 the ring 98 is also shown in its mid or neutral position withvthe gear teeth 99 and |00 out of mesh with the teeth they are adapted respectively, and alternatively, to engage.

If now, the upper end 'of the control lever is moved to the left, as viewed in Fig. 3, and then pulled backwardly from the position shown in Fig. 6 the following action takes place. The sidewise movement of the upper end of the lever to the left as seen in Fig. 3, will move the lower end to the right, as viewed in this figure and will rotate lever I2I, pin |06 and yoke |01 in clockwise direction,` as viewed from above in this figure. This will result in movement of the arms |09 of Y yoke |0I and the blocks carried by the arms into the pla-ne o f the paper, as viewed in Fig. 3 and rearwardly of the transmission, as viewed in Fig. 1, thus causing meshing of teeth 93 and 99.

The backward pull of the upper end of the control lever, that is,"to` the right as viewed in Fig. 6, will cause movement of yoke II (Fig. 2) through the medium of the link I|8 so as to shift the part 64 (Fig. 1) rearwardly to the position shown in Fig. l. This will result in moving ring part 52 forwardly to the position shown. Ring part 52 exerts engaging pressure against clutch plate 4 9 -because of the spring action of the spring plate 60, which it will be noted is dished and in tending to straighten itself exerts pressure on the levers 51 in a manner causing them to force the pins 56 forwardly. With the clutch mechanism in this position it will be evident that power will beA quently, the shaft part 2| and the impelled part of the secondary member of the hydraulic mechanism will remain stationary. Also, from Fig. l it will be evident that power will not be transmitted to the primary member of the hydraulic mechanism-since the clutch plate I9 is free.l This prevents loss of power due to rotation of any part of the hydraulic mechanism when vpower is transmitted through shaft 4,6. l

Meshing ofthe teeth 93 and 99, due to the lever locks the part 86, and consequently the pins upon which the planetary pinions 95 are mounted, againstrotational movement with respect to part 92, xed to the driven shaft 11. -With the pins upon which the pinions 95 are mounted locked against rotation relative to part 92 and with the teeth of these pinions meshing with teeth 94 on part 92, it will be evident that the pinions cannot revolve about their own individual axes, and they will consequently act as force transmitting parts for transmitting power from the part 00 fixed to shaft 46 to the part 92 ixed to the driven shaft 11. Direct drive is thus established through the transmission from shaft 50 to the driven shaft 11 by movement of the control lever, as assumed, to the f 'On the other han'd this movement will shift part 'i 64 forwardly, or to the left as vseen in Fig. l., and this will result in a shifting of the levers 51 to pull the clutch ring 52 to the right in the ligure so as to release the clutch plate 55 and cause engagement between the ily-wheel parts and the clutch plate I9. that due to the movement of levers 51 yaround their radially i'lxed pivots, the spring plate 60 will be dished by an increasing amount until the levers 51 have passed dead center position and will then be dished by a decreasing amount as the innerends of the levers move forwardly from dead center position. This arrangement provides a toggle action such that the spring plate will operate to exert pressure on clutch plate I9 whenthis clutch is engaged, in the same manner that From Fig. 1l it will be evident it exerts engaging pressure on clutch plate A9 in y the position shown of the parts shown in Fig. 1.

When power is transmitted through clutch plate I9, the primary member of the hydraulic mechanism/is rotated in clockwise direction as viewed from the left of Fig. 1 and the impellery blades I'I circulate the operating fluid in chamber II radially outwardly through these blades, then through the first row of turbine blades 2l, the row of xed guide blades 26 and the second row of turbine blades 24. Circulation of the operating fluid in the closed path of lflow provided in chamber II transmits power to the driven member of the hydraulic mechanism in the mannerl more fully described in Pat. No. 1,900,118 granted March '7, 1933 on the application of Alf Lysholm, to which reference may be had for a more complete description of the operation of hydraulic variable-speed power transmitting mechanism of the general type herein shown.

Rotation of the secondary member of the hydraulic mechanism also in clockwise direction results in clockwise movement of the inner ring I8 of the overrunning clutch, as viewed in Fig. 3.'

vco

This causes the rollers 82 to grip and transmit power by way of the ring 8| to the part 80, from which motion is transmitted, without relative motion betweenthe parts, to the driven shaft l1. 'This position of the control lever provides forward variable speed drive through the hydraulic mechanism.

To reverse the direction of drive of shaft l1, the control lever is moved sidewise to the right as viewed in Fig. 3 and forwardly as viewed in Fig. 6. The forward movement of the lever will effect adjustment of the clutch parts so as to cause power to be transmitted through the hydraulic mechanism to the partl 80 in the manner just described.

The sidewise movement of the lever to the right (as viewed in Fig. 3) will, however, operate to shift ring 98 to the left in Fig. l and cause teeth |00 to mesh with the stationary teeth iill. I This locks part 36 against rotation and consequently fixes against rotation the pins upon which the pinion gears 95 are mounted. Also, due to the unmeshing of teeth 93 and 99, part 92 is free to revolve with respect to the part 80. With the parts in this relation, rotation of part 80 in clockwise direction causes rotation of part 92 in counter-clockwise direction, through the medium of the pinions 95, which revolve around their individual fixed axes. A

From the foregoing description it will be evident that the control arrangement provided is similar to conventional gear shift controls and means of any suitable nature may be employed to guide the control lever to its various operative positions. The -spring pressed block |2| shown in Fig. 4 serves to tend to hold the lever in neutral position, and forward and backward movement of the lever may be prevented by suitable blocks, one of which is shown at 26 in Fig. 4, except when the lever is shifted sidewise to engage either teeth 99 or |00. It will be evident that direct drive in reverse is ordinarily not desirable and any suitable stop means may be employed to prevent movement of the lever sidewise to the right as viewed in Fig. 3 and backward, which movement would cause engagement of the direct driving clutch plate 4S and engagement of teeth l|0|l with teeth i0! to transmit drive in reverse direction to shaft 1l.

Turning now more particularly to the details of construction shown in Fig. 1, it will be observed that by mounting the forward end of the. driven member of the hydraulic mechanism in a pilot bearing in the driving member, the main rotating parts of the hydraulic mechanism may be rigidly mounted within a comparatively short axial space, whichin the present embodiment is represented by the distance between bearings I2 and 22. 'I'he driving member is held in alignment between the spaced bearings I2 and lI3 and vthe driven member is held in Aalignment between the bearings 22 and 3 I. If it were not for mounting the forward end of the driven memberin the pilot bearing a second bearing rearwardly of bearing 22 would be required to hold this part in alignment and this would" involve additional axial length of they transmission. It will be appreciated that for automotive and like installations the saving in space is of material practicalimportance. It is evident that the efficiency of operation of the hydraulic mechanism will be greatly impaired by large clearances between the rotating members and the stationary casing parts and also by large clearances between the adjacent parts of the relatively rotating 'driving and driven members. By mounting one of the members in a pilot bearing in the other, it is evident that not only a relatively rigid mounting is obtained for -the Vmembers with respect to the casing but relative movement of one member radially with respect to the other due to worn bearings is also minimized. This construction enables close initial clearance to be employed and materially assists in maintaining the initial close clearances over long continued periods of use.

By making the driving and driven members with coaxial hollow shaft parts a simple and convenient direct drive arrangement is made possible and by means of the pilot bearing and packing arrangement shown any substantial amount of leakage of operating iiuid from the chamber through the hollow shaft parts is prevented. It will further be noted that the arrangement shown provides for separation of the ball bearings from contact with operating fluid so that these bearings may-be adequately lubricated with suitable lubricating oil. The pilot bearing is preferably, as shown, a plain journal bearing and adequate lubrication of this bearing may be obtained from the operating fluid which is usually of some relatively oily character. For

example, we have found a most satisfactory operating uid to be kerosene containing a small quantity, such for example as about ve percent, of lubricating oil. Journal bearing i3, however, may be lubricated from an external lubricator through the channel |21.

Such operating uid as may leak past the several packings to the interior of the hollow shafts i5 and 2| is preferably kept from flowing longitudinally by means of suitable internal recesses in these parts and ridges on the shaft 46, the recesses being connected through drain channels for conducting the fluid from the transmission. These drain channels need not be described in detail.

The advantage of the reverse gear arrangement is. more or less self-evident since this arrangement provides a vgear of an axially compact nature which, taken in conjunction with the manner of mounting the main rotating members of the hydraulic mechanism, enables the entire transmission to be made with a minimum longitudinal over all length. At the same time the reverse gearing shown requires comparatively little space transversely.

Turning now to the form of transmission shown in Figs. 7 to 12, the clutch arrangement at the forward end of the transmission is similar toV that previously described and is controlled by means of a suitable yoke having an arm extending through the transmission casing similar to the arm 1 6 shown in Fig. 6. In the present embodiment `the'driving member of the hydraulic mechanismrcomprises a hollow member |5a and a disc-like impelli part |6a carrying a ring of impeller or pump blades I'Ia. The driven member comprises a hollow shaft part 2 a and a turbinepart 23a, the latter carrying three rows of turbine blades 21a, ,2Ia,\and |28. The inner ends of the pump blades Ila are carried by ring |8a and the inner ends of turbine blades |28 carry ring member 25a to which the blades 21a and 20a are attached. 'I'he outer ends of blades 21a are attached to a ring |29 and the outer ends of blades 24a are carried on ring |30. Rings of stationary guide blades 28a and |3| are carried by the casing, the inner ends of blades |3| being connected by a ring 30a situated in a suitable recess in the part 25a. It will be evident .2,103,534 that as the operating fluid is circulated in the closed path of `fio'w inthe chamber lia, it. will tend to leak out from its confined path through the clearance spaces between the relatively mov, ing ring parts and between some of these ring parts and the walls of the casing |a which together with these parts define the path of flow. Such leakage is detrimental to the efficiency ofv operation ofthe transmission mechanism and in order to minimize this leakage we provide between theseveral relatively rotating parts cooperating projections and recesses which form in i eilect labyrinth packlngs providing substantial resistance to leakage ow. This construction is shown more clearly in Fig. 1-1 with respect to the part 29a fixed to the transmission which carries the row of stationary guide blades |3-|, and the "rotating parts 23a and |30. Part 29a is flanged at 32 and |33 and these flanges are recessed at |34 andV |35 respectively. Parts 23a and |30 are similarly flanged and the flanged portions are provided with recesses |36 and |31 which cooperate respectively with recesses |34 and |35 to provide what may be termed` labyrinth packings comprising series of spaced narrow clearance spaces and |39. The narrow clearance spaces separated by the recesses provide a tortuous path of flow for operating fluid the nature of which tends to create turbulence vin theow of fluid tending to leak, and 'consequently minimizes leakage.

Similar labyrinth packing is provided between other of the relatively rotating parts, as for example, asindicated generally at |30 in Fig. 11. It will further be 4evident that the operating fluid circulating, inthe closed path of flow. will exert axial pressure on the parts |Ba and 23a.,Y

1 tending to force them axially apart. This thrust is balanced. to a substantialdegree by the presrsure of iluid in the spaces |4| and |42 provided v between stationary casing parts and the parts Ilia, and 23a respectively. Fluid under 'pressure en-v ters space |4| by way of the clearance space between ring |29 and the casing |0a and fluid en ters space |42 by way ofthe'clearance space bef tween the ring |30 and the 4casing Illa. In order to Aprevent the relatively high pressure prevailing This baille serves lto'maintain the fluidin theV v nular extension |50 :on the in spaces |4| and- |42.'from reaching the radially inner portion of the apparatus, labyrinth packings |43 and |44 are provided between'parts IBa yand 23a, respectively; and adjacent parts of the stationary casing structure. These packings comprise cooperating projections and recesses similar to those described above with reference to Fig. 1l.

It will be noted thatthere is a relatively large space |45 between the -main casing and the ra- -dially inner partiof `the part 23a and in orderv to minimize loses due. to turbulence of fluid. in this space a stationary baille plate is provided,

adjacent to the radially inner portion of part 23a.

space |45 in substantial quiescent' state evenwhen theturbine member is rotating.

The pilot bearing arrangement in the present modification isdifferent from that shown in Fig. .v -l, the driven member in this instance 'being rotatably supported in the casingby the ball bearing 22a' and the ljournal bearing Ha, the latter being formed in the stationary casing'part |41. ',Th'e turbine part 423a. pro"vides a cylindrical journal |40 'for the ,pilot bearing |43 formed in" the'animpeller part Ida o! the driving member. The drivingrnemberis support'ed by pilot bearingv |49 and ball bearing Ifa.

fand expand so as to It will be evident that this arrangement provides the same compactness and insures the same alignment of parts as the arrangement previously described in connection with Fig. 1.

As in thearrangement shown in Fig. 1, packings are provided between the casing and the driving and driven members of the hydraulic mechanism and packing is provided between these members. t 'I'he construction and arrangement of the packings is substantially the same as that previously described and need not be again described in detail. y

Means for transmitting power from the central shaft 45a or from the hollow shaft part 2|a fof' the hydraulic mechanism to the driven/shaft is diierent from that shown in Fig. 1 and comprises friction clutch apparatus the nature of which facilitates manipulation of thel means for controlling the transmission.

In the present embodiment the rearward end of the central shaft 56a is splined in a recess |5| at the forward end of the driven shaft part 11a so that this central shaft forms in eect a continuation of the driven shaft extending through the transmission to the clutch plate.

The rearward end of the hollow shaft-Ela has' xed to it the inner ring ita of the overrunning clutch, the outer ring 8m ,of which is fixed insldetheforward end of the annular member a which is rotatably supported in ball bearings |52 'and |53. Adjacent to its rearward'end the part 80a has xed thereto a ring carrying external' on an axially shiftable sleeve a which at its rearward end is provided'wlth axially extending teeth 99a. adapted to engage teeth 03a 'fixed with respect to the part da. Part Sla has secured thereto the axially `extending part 92a having internal gear teeth 94a. 'Ihe pins 01a carry pinions l95a, the teeth of which mesh with teeth 06a and teeth 96a.

fastened to the stationary part |55 fixed to the casing. Spring |56 is surrounded bya stationary sleeve H56, there being sufcient'space between parts- 08a.' and |56l to permit the spring to uncoil be out of contact with part As'shown in Fig. 10, the rearward end of spring |54 has fixed thereto a lug |51 to which is pivotally connected bymeans'of pin |53 a link` I 59. Sleeve |56 is extended and provided with a sloty |60 serving as a guide for pin |58.

. Yokelll'la is pivoted vin the casing and is provided with arms, one of which is shown at |090 in the n gure. This arm carries at its lower end .the block |||a iltting inthe groove |03a' in the sleeve 90a. The other armof the yoke carriesa similar arm IBI yextending substantially at 'rightlangles' y 1 50 A heavy coil spring `|54 is disposed around the sleeve 98a the forward'end of the spring being block situated in groove |03a. Yoke. llahas an r to the arm |08a and having at its outer end a.

roller |32. A spring lcarried in'-` agsuitable retainer in thehousingbears against arm ill as indicated in Fig. 10.l I

A shaft |04 rotatablymounted in the side 'of the casing and extending therethrough has fixed at its inner end a cam plate |65 against whichA the roller |62 bears. Plate |65 carries a projecting pin |66 and this pin is located in an open endedslot |61 at the end of link |56.

It is to be noted that -cam plate |55 is provided with circular cam surfaces |68 and |69 of differ- Fig. 12) meshing' with the beveled sector |12 rotatably mounted in the housing |13 bolted to the main transmission casing, A control shaft |14 is provided with a splined portion passing through a suitable splined bore in the sector part |12. to part |12 but by means of the splines is rotationally fixed with respect thereto.

The operation of this mechanism in the different control positions is as follows. When the control lever, which may be similar to that ldescribed in connection with Fig. 1 and related figures, is moved so as to cause the central shaft 46a to be directly 'connected to the power shaft, direct mechanical drive is effected to the driven shaft 11a through the splined connection in the recess |5|. Assuming that the axially shiftable sleeve 98a is in a position' to the right of that shown in Fig. 7 with teeth 95a and 69a in mesh, the parts 92a, 98a, 95a, 86a, and 60a will revolve as a unit without relative motion between the parts due to the connection between these parts and the driven shaft part 11a through the flange 9|a. Rotation of part 80a and the outer ring 8|a of the overrunning clutch, without rotation of the driven member of the hydraulic mechanism, is permitted because of the action of the overrunning clutch 19 between parts 2|a and 80a.

In order to insure freedom of rotation for the part 68a under theassumeddirect drive conditions, the shaft |64 must be rotated in clockwise.

direction from the position shown in Fig. 10 to a position such that roller |62 is moved from the cam surface |68 to the cam surface |69. This movement will cause pin |66 to first move to the bottom of the slot |61 and then to move link |59 downwardly as viewed in Fig, 10. This movementwill evidently uncoil spring |54 so that it will not be in contact with sleeve 98a and -the latter will be free to rotate insofar as spring |54 is concerned.

When the cam plate is moved in clockwise direction to bring roller |62 into contact with the cam surface |69 spring |63 will cause roller |62 to follow the cam surface and will cause the yoke |01a to move in counter-clockwise direction as viewed in Fig.l 10. This will move block la and its companion block rearwardly of the transmission to shift sleeve 96a into the position already assumed, that is, with teeth 93a and 99a in mesh.

When the transmission clutches are shifted to provide forward drive through the hydraulic y mechanism, the transmission of power from the hydraulic mechanism to the driven shaft member 11a is as follows. The hollow shaft part 2|a is rotated in clockwise direction as' viewed from the left in Fig. 1 and as viewed 'in Fig. 8. thus causing the overrunning clutch to turn part a, the teeth 66a of which are in mesh with the teeth of`pinions a. Due to the fact that the part 66a carrying the pins 81a upon which the pinions are mounted is held against rotation with re- Shaft |14 is slidable axially with respect spect to the part 9|a by virtue of the-connection through the part 98a and the meshing teeth 63a and 99a, and that'the teeth of the pinions 95a are in mesh with teeth 94a, on the part 92a Whichis also fixed against rotation with respect to part 9|a, the pinions are'prevented from rotating about their own individual axes and-act as direct drive connections for transmitting `power from the part 80a to the part Sla. and

consequently to the driven shaft part 11a. Thus, direct drive is established between the driven member of the hydraulic mechanism and theV driven shaft of the transmission, speed reduction between the power shaft and the driven shaft of the transmission being effected in the hydraulic mechanism. In orderto effect drive in reverse direction of the driven shaft part 11a, the shaft |64 is rotated to the position shown in Fig. 10. When roller |62 is forced up on to the cam surface |66 it moves the yoke |01a to the position shown in this figure which corresponds to the position of the parts shown in Fig. '1, thus causing sleeve 98a to be shifted to the position shown in Fig. 7, with teeth 93a and 99a out of mesh. At the.same time the expanding pressure exerted by link |59 on spring |54 is relieved and the spring contracts and wraps itself around sleeve 98a. The spring is coiled so that tendency of sleeve 98a to rotate under the influence of force Y' causes the pinions 65a to rotate labout their own axes, which are held stationary due to the connection between part 66a and sleeve 98a. Pinions 95a transmit motion in reverse direction from part 80a to the part 92a, causing the latter, and consequently the driven shaft part 11a, to rotate in counter-clockwise or reverse direction, as

lviewed from the left of Fig. '1.

When the parts are set for reverse drive, as shown in Fig. 10, it will be observed that some lost motion or clearance is provided between pin |66 in the bottom of slot |61. This insures freedom of spring |54 to wrap itself tightly about the sleeve 98a so as to lock the sleeve firmly against rotation.

The projecting end of the yoke lever 16 for controlling the clutches and the shaft |14 (Fig. 12) for turning shaft |64 to control the direction of drive may be combined so as to be operated from a single control lever of ,the type shown in Fig. 6 in any suitable manner.

One suitable form of apparatus for connecting these parts to a single control lever isI dis-r closed in Pat. No. 1,900,119, previously referred to, and-to which reference may be had for suitable details of construction.

It will be evident that the general mode of ooeration of the transmission just described is the same as that described in connection with Fig. 1v

and related gures. 'Ihe present embodiment, however, provides important advantages in the control of the transmission by virtue of the inolusion of the friction clutch provided by spring' sible for the driving and driven members not only to rotate in the same direction at different speeds but to rotate in opposite dircetions and for this reason it is possible, without damage to the transmission, to have the transmission set for reverse drive when the vehiclein which the transmission c is mounted is moving forwardly and with the engine delivering powerto invoperation. Due to the employment of friction clutch means for locking sleeve 98a so as to effect reverse, it is possible to shift the control of the transmission to reverse position with the vehicle moving forwardly without damaging any of the transmission parts and when this is done it will be evident that the hydraulic mechanism will pro.` y

vide an extremely powerful braking agency due to its tendency to transmit motion in reverse direction to the driven shaitoi the vehicle'. The transmission thus makes available to the operator of the vehicle what may be said to be a motor or engine actuated hydraulic brake operating through the usual drive line of the vehicle to apply braking action to the drlvemwheels of the vehicle.

Turning now more particularly to Fig. 13. another arrangement is shown for mounting .the driving and driven members of the hydraulic mechanism. In this arrangement plain journal bearings are used throughout. The driving member |4111` comprises the hollow shaft part |5band impeller part |611 and is mounted in a plain bearing in the casing |0b, indicated generally at |15.

This bearing comprises a cylindrical bearing surface |15a and a radially extending bearing sur face |15b so that the bearing provides not only radial support for the driving member but lalso provides a surface for preventing axial displacement ofthe driving member. y

The ,driven member 20h is mounted in the casina by bearing` |16 having a cylindrical Iportion |16a. and a radially extending bearing surface |1611.' The shaft part 2lb ofthe driven member is provided with a forwardlyproiecting annular extension |11 projecting into a suitable recess in the extension |18 of the driving member Hb. Extension |11 is journalled in the driving member by means 'of `a pilot bearing which in the present instance comprises the spaced cylindrical bearing surfaces |19 and |80 anda radially extending bearing. IBI provided between the driven member 20b`and the radially 'extending extension |18 on the drivingvmember no. From the drawings it' will be evident that the above described bearing arrangement provides for holding the driving and driven members of the hydraulic mechanism in proper coaxial alignment with respect to each other and with respect to the casing and also provides against axial end play of the members both 1 with respect to each other and with respect to Vthe casing.

In this arrangement, as in the arrangements previously described, packing is provided between the driving yand driven membersfor preventingr flow of iiuid to the space in which the central shaft |16 is located. This packing it will be observed is in all the several embodiments arranged with respect to the pilot bearing so that any fluid passing from' the working chamber of the transmission to the space in which the direct drive shaft is situated must force its way serially past bearing surfaces of considerable area and also past the packing, which may be said to be arranged in series with respect to the bearing surfaces with respect to leakage flow.

. This minimizes possibility Yof leakage` of operthe driving member Y this pointand also minimizes the possibility of air of operation which might produce negative pressure ofthe operating uid in the radially inner portion of the operating chamber.

In 'the present embodiment packings of the type already described are provided between the hollow shaft parts |5b and 2lb and the casing to prevent leakage of operating fluid around the outside of these shaft parts.

In all of the hydraulicmechanisms hereinbe fore described, it is desirable to maintain the operating fluid under some degree of positivepressure so as to prevent ingress of air to the operating chamber and it is also desirable to continuously withdraw a certain amount of operating uid from the operating chamber to cool it, the operating iluid lost from the chamber due to leakage andl withdrawal for cooling purposes being continuously replaced by make-up fluid supplied to the chamber. For effecting this we prefer to employ apparatus constructed in accordance with the disclosure in U. S. Pat. No. 1,934,936 granted March '1, 1933 on the application of Alf Lysholm,

'to which reference may be had for .details not shown in this application.

In considering the several .embodiments hereinbefore described, it will be noted that the blading arrangement in the hydraulic power trans mitting mechanism in the embodiment shown in Fig. 1 is somewhat different from'that illustrated.

in Figjf. The form shown in Fig. 1 employs two rows of turbine blading, while that illustrated in Fig. 7 employs three rowsV of turbine blading. Somewhat lower maximum 'eiliclency may be expected from the formhaving two rows of turbine.v

blades, but the 'form having two rows of turbine blades may be made smaller in diameter 'and lighter and is consequently better adapted for installation in automobiles and thelike of the pleasure type as distinguished from heavier vehicles such as buses and trucks. The pleasure vehicle type is normally operated for only a small percentage of the total time of operationwith a speed-reducing gear ratio, operation during the major 4portion of the time being in direct drive. Consequently, somewhat lower efliciency in the hydraulicmechanism than that which it is possible to obtain is satisfactory in view of the advantages obtained with respect to weight and space occupied.

With aliv of the forms of transmission illus` trated it will be observed,however, that the utmost compactness is obtained because of the form of construction of the clutch mechanism for the alternatively engageable clutches, the hydraulic embodied in many diiferent forms of apparatus and that some of the features of the invention may be employed to 'the exclusion of others.

Certain features of the invention dealingwith the hydraulic parts o the apparatus form the claimed subject matter of our divisional application Serial No. 754,080, led November 21, i934.

What is claimed is: A 1. A variable-speed power transmission comprising a driving shaft, a driven'shaft, afirst means comprising a releasable clutch for transmitting power mechanically from the driving` shaft to the driven shaft, a second means for transmitting power from the driving 'shaft to the driwen shaft, said second means comprising Vhydraulic variable speed power transmitting mechanism having a driven member, a second releasable clutch foratransmitting power from the driving shaft to said hydraulic variable speed mechanism, mechanism for transmitting power from the driven member of the hydraulic mechanism to said driven shaft'comprising planetary gearing and mechanism including frictionally engaging parts for controlling said planetary gearing to cause power 'to be transmitted directly through the gearingin one position of the control means and to cause power to be transmitted to the driven shaft in reverse direction through the gearing in another position of the vshaft to the driven shaft,

controlling means.

2.' A variable-speed power transmission comprising a driving shaft, a driven shaft, a rst means comprising a releasable clutch for transmitting power- -mechanically from the driving shaft to the driven shaft, a second means for transmitting power from the driving shaft to the driven shaft, said second means comprising hydraulic variable-speed power transmitting mechanism having a driven member, a second releasable clutch for transmitting power from vthe driv- .ing shaft to said hydraulic'variable speed mechanism, mechanism for transmitting power from the driven member of the hydraulic mechanism to said driven shaft comprising planetary gearing and an overrunning clutch arranged in series in the path through which power is transmitted and mechanism including frictionally engaging parts for controllingv said planetary gearing to cause power to be transmitted directly through the gearing in one position of the/control means and to causepower to be transmitted to the driven shaft in reverse direction through the gearing `in another position of the' controlling means,

said overrunning clutch providing a release permitting the driven member of the hydraulic mechanism to remain stationary when 'poweriis transmitted to the driven shaft through said first means.

3. A variable-speed power transmission comprising a. driving shaft, a driven shaft, a flrst means comprising a releasable clutch for transmitting power mechanically from kthe driving a second means for transmitting power from the driving shaft to the driven shaft, said second means comprising hydrauli'c variable-speed power transmitting mechanism having a driven member, a second releasable clutch for transmitting power from the driving shaft to said hydraulic variable speed mechanism, mechanism for transmitting power from the driven member of the hydraulic mechanism to said driven shaft comprising planetary gearlng and means for controlling said planetary gearing to cause power to be transmitted directly through the gearing in one position of the control means and to cause power to be transmitted to the driven shaft in reverse direction through the gearing in another position of the controlling means, said planetary gearing comprising a rotatably mounted carrier for the planetary gears arranged to cause reversal of the direction of drive to the `driven shaft when the carrier is prevented from rotating and said controlling `means comprising a releasable friction clutch casing, hydraulic variable-speed power 'transmitting mechanism comprising a driving meme shaft part and an impeller part andthe driven member comprising a hollow shaft part and an impelled part, said impeller and impelled parts being located in a common chamber for operating fluid in said casing and being arranged to transmit power from the impeller p art to the impelled part and said hollow shaft, parts being arranged in axial alignment centrally of the casing, a shaft connected to the other of said clutches and extending through said hollow shaft parts, a driven shaft and means for transmitting power either from said driven member or the firstmentioned shaft to the driven shaft comprising planetary gear mechanism and an` overrunning clutch arranged in series in the line of power transmission between said driven memlber and said driven shaft, said overrunning clutch permitting lsaid driven member to remain idle when power is transmitted to the driven shaft throughthe rst mentioned shaft and said planetary gearing providing for drive in either direction of the driven shaft from the driven member of the hydraulic mechanism, mechanism including frictionally engaging parts for controlling said @planetary gearing, and means for delivering power to one or the other of said alternatively engageable friction clutches.

5.,`Variable speed power transmitting mechanism for vehicles comprising a driving shaft, a driven shaft mechanically connected to the wheels of the vehiclel a driving member comprising a pump part adapted to be driven by' said driving shaft, a driven membercomprislng a turbine part adapted to be driven in one direction onlyby fluid circulated `by said pump part, means for directly connecting said driving shaft and said driven shaft, means for selectively causing power to be transmitted from said driving shaft to said driving member or directly to the driven shaft, means including a free wheel clutch and a planetary reverse gear for transmitting power from said driven member to said driven shaft,V said reverse..gear being located between the free wheel clutch and the driven shaft in the line of power transmission, and means including frictionally engaging parts for controlling said planetary reverse gear whereby to permit the reverse gear to be engaged to provide reverse rotation -of the turbine part with respect to said driven shaft when the driven shaft is turning in the direction corresponding to forward motion of the vehicle.

6. A variable speed power transmission compart having a plurality of stages of bladlng and k said pump part and said turbine part being arranged for circulation of operating uid in a closedv path of flow to effect torque multiplying transmission of power from t. -e shaft part of the driving member'to the shaft` part of kthe driven member, reverse gear mechanism for transmit-V ting power 'from the shaft part of said driven-V member to a driven shaft? and mechanism including frictionally engaging parts for controlling said reverse gear mechanism. whereby to permit the reverse gear mechanism to be eni gaged -to effect reverse rotation of said driven member and said `driven shaft with respect to each other while said driven shaft is in motion.

. member comprising a turbine wheel located in s aid chamber and having a plurality o f stages of blading, said turbine wheel being adapted to be driven in one direction only by operating.

fluid circulated in said chamber by said pump wheel and said driving member and said driven member cooperating to multiply the torque delivered by the driving member, planetary gear mechanism for transmitting power from said driven member selectively in either direction of rotation toa driven shaft and mechanism in- 2'0 cluding frictionally engaging parts for controlling said planetary gear mechanism to permit the planetary gear mechanism to be engaged to i effect reverse rotation of said driven member and said driven shaft with respect to each other when the driven shaft is in motion whereby to provide a uid brake transmitting to said driven shaft a braking torque derived from said driving member and of higher value than the torque available at the driving member.

8. A variable-speed power transmission for transmitting power from a driving shaft to a driven shaft comprising 'hydraulic variablespeed power transmitting mechanism having a driving member and a driven. member, said members being rotatably ,mounted and having hollow shaft parts in coaxial alignment, an intermediate shaft extending through said hollow shaft parts land adapted to transmit power mechanically from the driving shaft to the driven 4. shaft, alternatively engageable friction clutches ing hydraulic power transmitting mechanism having fluid `circulating means and a turbine member adapted to be driven in one direction only by the circulation of said fluid, planetary rey verse gearing arranged in series in the line of power transmission from said turbine member to a driven shaft and means including frictionally engaging parts for permitting power transmitting connection through said gearing to be shifted to connect said turbine member to said turbine 50 shaft forvreverse drive of said driven shaft without shock due .to rotation of said turbine member in forward direction under the influence of the fluid circulating in said hydraulic mechanism..

10. A variable-speed power transmission com- 65 prising a driving shaft, adriven shaft, a first means comprising a releasable clutch for transt mitting power mechanically from the driving shaft to thedrlven shaft, va second means for transmitting power from the driving shaft tothe driven shaft, said second means comprising hydraulic variable-speed power transmitting' mechanism having a driven member, means for transmitting power from the driving shaft to said hydraulicvariable-speed mechanism, mechanism for transmitting power from the driven member of thehydraulic mechanism to said driven shaft comprising planetary gearing and means for controlling said planetary gearing to cause power to be transmitted directly through the gearing in one position of the control means and to cause power to be transmitted to the driven shaft in -reverse direction through the gearing inanother position of the control means. said planetary gearing comprising a rotatably mounted carrier for the planet gears arranged to cause reversal of the direction of drive to the driven shaft when the carrier is prevented from rotating, and said controlling means including a releasable clutch adapted to prevent rotation of said carrier.

11. In a variable-speed power transmission for transmitting power from a driving shaft to a driven shaft, a casing providing a chamber for therein to rotate said driven meinber,l a rotatably mounted central shaft member extending through the hollow shaft part of said `driven member, planetary gearing including a sun gear, a ring gear, planet gears and a carrierl for the planet gears, said sun gear being directly'connected to said central shaft part, clutch means for selectively establishing driving connection between said driving shaft and said central shaft part, 0,

clutch means for'transmitting power from said hollow shaft part to said 'sun gear and a power transmitting connection between said planetary gearing and said driven shaft. l

12. In a variable-speed power transmission forv transmitting power fronf a driving shaft to a driven shaft, a casing providing a chamber for operating fluid, a. driven member having a turbine part in said chamber and a hollow shaft part, means in said chamber for circulating the fluid therein to rotate said driven member, a rotatably mounted central shaft member extending through the hollow shaft part of said driven.

member, planetary gearing including a sun gear, a ring gear, planetgears and a carrier for the planet gears, said sun gear being directly connected to said central shaft part, clutch means for selectively establishing driving connection between said driving shaft and said central shaft part, clutch means for transmitting power from said hollow shaft part to said sun gear and clutch means for selectively connecting either said carrier or said ring gear to said driven shaft.

i ALF LYSHOLM.

FRED HORNEY. es'ra warmem. 

